"If Compaq had put a cellular radio in an iPaq, we would have had Windows Phones circa 2000, LONG before the iPhone."
We did have Windows phones long before the iPhone. We also had Palm phones and Symbian phones long before iPhone. There was an entire market full of such devices. Compaq was not needed to make that happen.
Those phones all had web browsers, too. Apple didn't invent that either, nor did Opera.
Apple's innovation with the iPhone was (a) a touchscreen keyboard that worked with your fingers, and (b) a platform that didn't crash daily. The form factor had already been done as had the basic UI. The iPhone wasn't even a smartphone at its introduction. It took another year before you could write apps for it.